feat(kernel-utils): make replaceNodeEnvPlugin NODE_ENV value configurable

Accept an options bag `{ value }` on `replaceNodeEnvPlugin`, defaulting to
`'production'`, so callers can inline a different `process.env.NODE_ENV`
value. Export the `ReplaceNodeEnvPluginOptions` type.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: rekmarks

packages/kernel-utils/CHANGELOG.md

@@ -13,7 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add an optional `required` field to `MethodSchema` (mirroring `required` on object `JsonSchema`) naming which arguments are required, and a `{ required }` option on `methodArgsToStruct` that validates unlisted arguments as optional, so a method's argument schema can faithfully represent the optional trailing arguments its guard already allows ([#958](https://github.com/MetaMask/ocap-kernel/pull/958))
 - Add `getLibp2pRelayHome()` to the `./nodejs` exports, returning the libp2p relay's bookkeeping directory (default `~/.libp2p-relay`, overridable via `$LIBP2P_RELAY_HOME`) — kept separate from `$OCAP_HOME` so one relay can serve daemons with different OCAP_HOMEs ([#952](https://github.com/MetaMask/ocap-kernel/pull/952))
 - `startRelay()` accepts an optional `publicIp` that is fed to libp2p's `appendAnnounce`, so a relay running on a NAT-backed host can announce its publicly-reachable IPv4 alongside its bound NIC addresses ([#952](https://github.com/MetaMask/ocap-kernel/pull/952))
-- Add `replaceNodeEnvPlugin` to the `./vite-plugins` exports, a Rolldown transform plugin that inlines `process.env.NODE_ENV` as the literal `"production"` in any module referencing it — used by `bundleVat` in place of a build-config `define`, so vats that pull in libraries like immer resolve the reference at bundle time ([#967](https://github.com/MetaMask/ocap-kernel/pull/967))
+- Add `replaceNodeEnvPlugin` to the `./vite-plugins` exports, a Rolldown transform plugin that inlines `process.env.NODE_ENV` as a string literal (configurable via `{ value }`, defaulting to `'production'`) in any module referencing it — used by `bundleVat` in place of a build-config `define`, so vats that pull in libraries like immer resolve the reference at bundle time ([#967](https://github.com/MetaMask/ocap-kernel/pull/967))
 
 ## [0.5.0]
 

packages/kernel-utils/src/vite-plugins/index.ts

@@ -5,6 +5,7 @@ import { bundleVat } from './bundle-vat.ts';
 export { bundleVat, removeDynamicImportsPlugin } from './bundle-vat.ts';
 export type { VatBundle } from './bundle-vat.ts';
 export { replaceNodeEnvPlugin } from './replace-node-env-plugin.ts';
+export type { ReplaceNodeEnvPluginOptions } from './replace-node-env-plugin.ts';
 
 type VatEntry = {
   /** Absolute path to the vat source file */

packages/kernel-utils/src/vite-plugins/replace-node-env-plugin.test.ts

@@ -55,4 +55,17 @@ describe('replaceNodeEnvPlugin', () => {
     const code = `const x = process.env.NODE_ENVIRONMENT;`;
     expect(transform(code, 'test.ts')).toBeNull();
   });
+
+  it('inlines a configured value instead of the default', () => {
+    const devTransform = replaceNodeEnvPlugin({ value: 'development' })
+      .transform as TransformFn;
+    const result = devTransform(
+      `const mode = process.env.NODE_ENV;`,
+      'test.ts',
+    );
+    expect(result).toStrictEqual({
+      code: `const mode = "development";`,
+      map: null,
+    });
+  });
 });

packages/kernel-utils/src/vite-plugins/replace-node-env-plugin.ts

@@ -1,8 +1,15 @@
 import type { Plugin as RolldownPlugin } from 'rolldown';
 
+export type ReplaceNodeEnvPluginOptions = {
+  /**
+   * The value to inline for `process.env.NODE_ENV`. Defaults to `'production'`.
+   */
+  value?: string;
+};
+
 /**
- * A Rolldown plugin that inlines `process.env.NODE_ENV` as the literal
- * `"production"` in any module that references it.
+ * A Rolldown plugin that inlines `process.env.NODE_ENV` as a string literal in
+ * any module that references it.
  *
  * This replaces the former build-config `define` (issue #812). Libraries such
  * as immer branch on `process.env.NODE_ENV`, and vats have no `process` global
@@ -13,9 +20,15 @@ import type { Plugin as RolldownPlugin } from 'rolldown';
  * {@link removeDynamicImportsPlugin}) and handles the dotted
  * `process.env.NODE_ENV` form, consistent with the `define` it replaces.
  *
+ * @param options - Plugin options.
+ * @param options.value - The value to inline for `process.env.NODE_ENV`.
+ * Defaults to `'production'`.
  * @returns A Rolldown plugin.
  */
-export function replaceNodeEnvPlugin(): RolldownPlugin {
+export function replaceNodeEnvPlugin({
+  value = 'production',
+}: ReplaceNodeEnvPluginOptions = {}): RolldownPlugin {
+  const replacement = JSON.stringify(value);
   return {
     name: 'ocap-kernel:replace-node-env',
     transform(code) {
@@ -25,7 +38,7 @@ export function replaceNodeEnvPlugin(): RolldownPlugin {
 
       const transformed = code.replace(
         /\bprocess\.env\.NODE_ENV\b/gu,
-        JSON.stringify('production'),
+        replacement,
       );
 
       if (transformed === code) {